Heat exchanger assembly



April 1 1970 H{ R. OTTO 3,506,192

HEAT EXCHANGE ASSEMBLY Original Filed Nov. 28, 1967 2 Sheets-Sheet 1 FIG-l 5 Q INVENTOR HOWARD R. OTTO fl/f ATTDRNEY April 14, 1970 H. R. OTTO 3,506,192

HEAT EXCHANGE ASSEMBLY Original Filed Nov. 28. 1967 2 Sheets-Sheet 2 FIG- 3 M/VE/VTGR HOWARD R. OTTO fl ATTORNEY United States Patent O Int. Cl. F28f 13/08 US. Cl. 236-34.5 3 Claims ABSTRACT OF THE DISCLOSURE A heat exchanger assembly in which a plate and fin type heat exchanger has uniquely formed plate components for simplified assembly and cooperates with manifolding means mounted to faces of the heat exchanger, the manifolding means including a fluid flow control valve of novel adjustment characteristics.

This application is a division of my copending application Ser. No. 686,124 filed Nov. 28, 1967.

This invention relates to heat exchange apparatus and has particular, although not limited, reference to plate and fin type heat exchangers and unitarily mounted manifolding and valve means.

An object of the invention is to provide a generally new form of valve control in the manifolding means lending itself to simplified installation and removal and to calibration which does not require repeated assembly and disassembly of the valve.

Other objects and structural details of the invention will appear from the following description, when read in connection with the acccompanying drawings, wherein:

FIG. 1 is a view mostly in vertical longitudinal section of a heat exchange device in accordance with the illustrated embodiment of the invention;

FIG. .2 is a view in horizontal longitudinal section through the heat exchange component of the device, showing a fragment of manifolding means at one end thereof;

FIG. 3 is a view in end elevation of the device, showing the closed end of the heat exchange component;

FIG. 4 is a detail view of the open side of the heat exchange component, being taken substantially along the line 44 of FIG. 1;

FIG. 5 is a view similar to FIG. 4, showing the open end of the heat exchange component, being taken substantially along the line 55 of FIG. 1;

FIG. 6 is a detail view in perspective of one of the plate element used in the heat exchange component;

FIG. 7 is a detail view in perspective of the other plate elements used in the heat exchange component; and

FIG. 8 is a detail fragmentary view of a corner of the heat exchange component showing how a drain opening useful in fabrication of the device is formed.

Refering to the drawings, the invention is disclosed as embodied in a device effecting a controlled circulation of two confined fluids in heat transfer relation to one another. Liquid to liquid heat transmission is provided for, the device of the illustrated embodiment of the invention being particularly adapted for the cooling of oil in an aircraft or like engine by reference to the relatively cool flowing engine fuel.

The device comprises a heat exchange component 10 and a valve-manifold component 11, mounting brackets 12, 13 and 14 being attached to or forming integral parts of the respective components and serving installation purposes.

The heat exchange component 10 is comprised of stacked plates 15 and 16 (FIGS. 6 and 7), and interposed fin strip material to be subsequently identified, the resulting assembly of parts forming a plate and fin heat exchanger wherein different fluids flow in adjoining passages for a transfer of heat between separating passage walls. Each plate 15 is rectangular in shape. It is made of a flat, heat conductive, sheet-like material, for example sheet aluminum. Opposite end extremities of each plate are bent upward and then inward. The result is that the ends of the plate are channel shaped and provide seats 17 raised from the flat planar surface of the plate proper. One side margin of each plate :15 is reduced in length to form in effect a projecting tongue which is bent upward and inward to form a seat 18 which extends between and substantially interconnects the seats 17. The length of seat 18 is substantially equal to the distance between the end seats 17. On the other side margin of each plate 15 a smaller length tongue is similarly bent upward and inward to form a seat 19, all of the seats 17, 18 and 19 lie substantially in the same plane. The relatively shorter length of seat 19 defines at opposite ends thereof flow openings 21 and 22.

Each plate 16 is formed similarly to the plate -15 except that in this instance both side margins of the plate are bent upward and inward and define substantially coplanar seats 23 and 24. One end of each plate 16 is bent upward to lie between and interconnect the seats 23 and 24, an end seat 25 being thereby formed. The opposite end extremity of each plate 16 is unformed.

In a stacked relation the plates 15 and 1-6 have a common orientation. The formed sides thereof, that is, the sides on which the seats 17-19 and the seats 2325 are formed face upwardly. The marginal seats of each underlying plate provide a rest for and support the flat undersurface of a next adjacent overlying plate. Further, all plates 15 face in a common direction and all plates 16 face in a common direction. The plates 15 and 16 are, moreover, stacked in an alternating relation. One side of the resulting assembly since it presents the fluid flow openings 21 and 22 may be considered the open side of the assembly. The opposite side is closed. One end of the assembly, since it is comprised in part of the unformed ends of plates 16 may be considered the open end of the assembly. The opposite end is closed.

The fin strip material which, as described, is interposed between adjacent plates 15 and 16 includes a strip 26 placed on the formed side of each plate 15 in a manner to be confined by the bent over seats 1719. The strip 26 is formed with corrugations of longitudinal extent and has a height substantially to equal the height of seats 17-19. The strip is positioned so that the corrugations run lengthwise of the plate or in a direction from end to end thereof. At its ends the strip 26 is cut away to define within the confines of end seats 17 generally triangular chambers 27 and 28. Within chamber 27 is a segmental strip 29 of fin strip material constructed like the strip 26 and having the same height but arranged with its corrugations extending lengthwise of the chamber 27 or at right angles to the corrugations of strip 26. In the chamber 28 is a similar strip 31. The chambers 27 and 28 align at their broader ends with the fluid flow openings 21 and 22.

In each plate element 16 is longitudinally disposed a spacer bar 32. The bar 32 is centrally positioned between the side seats 23 and 24. One end thereof coincides with the unformed end of the plate. The bar is shorter than the plate 16 so that the opposite end thereof terminates short of the formed or opposite end of the plate. On each side of the bar 32 are respective strips 33 and 34 of fin material, the fin corrugations extending lengthwise of the plate. One end of each strip 33- and 34 is square to coincide with the corresponding end of bar 32 and with the unformed end of the plate. The opposite ends of the fin strips are cut away along tapered lines to define at what may be considered the closed end of the plate an interior chamber 35.

The fin strip material is installed in the plates 15 and 16 prior to assembly or stacking thereof. The height of the strip material, since it coincides approximately to the height of the marginal seats on the plates provides that it shall be in contact with the flat undersurface of overlying plates. The fin strip material accordingly constitutes extended heat transfer surface, in effect projecting intervening passage walls into the path of flowing fluids. A core assembly includes a plurality of plates 15 and 16 stacked in an alternating relation with strip fin material interposed as described. A fiat plate 36 seats on the uppermost plate element, closing the upper end of the core. A stacked core has its component elements joined together in a unitary relation, as by a brazing or like operation. In the brazing process, adjoining plates are secured together along marginal seats and the fin strip material is made to adhere to the sides of confining seats and to overlying and underlying piate surfaces. The structure presents on what has been termed the open side of the device a vertical series of flow openings 21, and, longitudinally spaced therefrom by the turned up seat 19 a vertical set of flow openings 22. The open end of the device is similarly separated by the ends of spacer bars 32 into laterally spaced apart fluid flow openings.

The valve-manifold component 11 includes a valve body 37, a manifold section 38 adapted to make contact with the open side of the heat exchanger component and with another manifold section 39 bent at right angles to the section 38 to contact the open end of the heat exchanger component. A further manifold section 41 also contacts the open end of the heat exchanger component and may be an integral part of the component 11 or, as shown, may be a separate element attached to the section 39.

The manifold section 39 has a flange-like configuration to engage the heat exchanger component along marginal edges thereof. It has, further, interior flanges 42 and 43 engaging the open side of the heat exchanger component intermediate the flow openings 21 and 22. The arrangement accordingly is one to define within manifold section 38 a chamber 44 in common communication with all the inlet openings 21 and a chamber 45 in common communication with all the fiow openings 22. Manifold section 39 has a flange marginally contacting one side edge of the heat exchanger component, top and bottom edges thereof and a vertical line of contact defined centrally of the open end of the heat exchanger by the ends of aligned spacer bars 32. A chamber 46 therein communicates with the set of flow openings to one side of spacer bars 32. The manifold section 41 contacts one side edge of the heat exchanger component, top and bottom portions thereof and the exterior of section 39. The arrangement is one to define a chamber 47 in common communication with the lateral set of flow openings to the other side of the spacer bars 32. The valve-manifold component is advantageously welded to the heat exchanger component,

elds being formed as indicated along the several lines of contact of the respective described manifold sections with the heat exchanger component.

In the valve body 37 is a chamber 48 communicating through a body port 49 with the chamber 44. Also in the valve body is a chamber 51 in open communication with chamber 45 and communicable through a body port '52 with the chamber 48. Also in the valve body 37 is a chamber 53 communicating through manifold section 39 with chamber 4:5. Manifold section 41 has an opening 54 therein communicating with chamber 47. Chambers 48, 51 and 53 are connected to the exterior of the valve body by respective openings 55, 56 and 57. All of the openings 54, 55, 56 and 57 are adapted to be connected in lines flow'mg fluid under pressure, the openings 55 and 56 in a system circulating a first fluid and the openings 54 and 57 in a system circulating a second fluid. In accordance withthe illustrated embodiment of the invention openings 55 and 56 are connected in a system circulating oil from and back to a source of heat, opening 55 serving as the oil inlet port through which heated oil from the source of heat is directed to the heat exchanger component while the opening 56 serves as the oii outlet port through which cooled oil is directed from the heat exchanger component back to the source of heat. Openings 54 and 57, in accordance with the invention embodiment, are connected in a system flowing fuel from a source to a place of use. In accordance with such embodiment, opening 54 serves as the fuel inlet port, fuel flowing from the source through such opening being directed to the heat exchanger component. Opening 57 serves as the fuel outlet port, fuel being directed therethrough from the heat exchanger component to the place of use.

In accordance with the mode of operation of the heat exchange device, oil enters the device by way of oil inlet port 55, flows through chamber 48 and opening 49 to chamber 44. There it has simultaneous access to all of the flow openings 21 and so enters the several flow passages defined by plates 15. The oil initially encounters strip fin material 29, is guided thereby interiorly of the heat exchanger Within chamber 27. From there it flows lengthwise of the heat exchanger along a path as defined by strip ma terial 26 to chamber 28 whereupon it turns and is redirected by strip fin material 31 to and through the flow openings 22. Emptying into chamber 45, the oil flows to chamber 51 and leaves the device by way of oil outlet port 56. Fuel entering fuel inlet port 54 is distributed in chamber 47 to flow simultaneously through the several plates 16 along paths as defined by the strip fins 33 along one side of the spacer bars 32. Entering chamber 35 at the far end of each plate 16, the fuel turns and flows in a reverse direction along the opposite side of bars 32 along fin strips 34, emptying into chamber 46. There the fuel is conducted by mainfold section 39 to valve body chamber 53 and leaves the device by way of fuel outlet port 57. In the presence of oil and fuel flows as described, it will be understood that some of the heat of the relatively higher temperature oil is transmitted through encountered fin strip material and through the separating passage walls to the lower temperature fuel. Oil leaving the device by way of oil outlet port 56 is conditioned to a lower temperature value suitably to its return to the heat source.

The body opening 52 provides for direct flow of greater or lesser portions of the oil admitted by way of inlet port 55 to outlet port 56 in by-passing relation to the heat exchan e component. By-passing flow occurs, under control of a valve 57, under conditions indicating excessive oil cooling or in the event that the difference in pressure value between inlet port 55 and outlet port 56 is such that heat exchange component 10 may be damaged thereby. The valve 57 is a disc-shaped member having a flanged periphery adapted to seat on a vertical partition 58 in which opening 52 is formed. The valve is in chamber 51 and seats to the partition 58 in a surrounding relation to opening 52 but in a manner to yield to relatively higher pressures in chamber 48 to move to an unseated, open position. Extending in one direction from the valve 57 is an integrally formed stem 59 received for relative longitudinal sliding motion in a bushing 61. The latter is formed integrally with a large diameter nut 62 having a screw threaded mounting in an end opening 63 in the body 37. End opening 63 and by-pass opening 52 are aligned. Nut 62 and bushing 61 are in concentric relation to opening 63 and so guide the valve 57 concentrically of bypass opening 52. A compression spring 64 is interposed between the back of valve 57 and an integral flange on bushing 61 in a manner to urge the valve yieldingly to a seated position on partition 58. The nut 62 acts as a closure cap for one end of the body 37 but is adjustable in a rotary sense from outside the body, the screw threaded mounting of the nut being such that rotary turning movement of the nut effects axial longitudinal adjustments thereof in a manner to vary the compression of spring 64. A cylindrical portion of nut 62 has a bearing in an inwardly projecting boss 65 of the body 37. A sealing member 66 is peripherally installed in such cylindrical portion to inhibit the escape of oil from chambers 45 and 51. The valve 57 is further formed with an oppositely projecting stem 67, extending to and through the by-pass opening 52 into chamber 48.

The end of body 37 opposite opening 63 is formed with another like opening 68, the openings 63 and 68 being aligned. An externally threaded nut 69 is rotatable iii the opening 68 and has a projecting sleeve portion 71 guided by a bearing surface 72.-A peripheral seal 73 in sleeve 71 engages surface 72 and inhibits escape of fuel from chamber 53. Centrally of the sleeve 71, the nut 69 is formed with a relatively shorter projection 74. Seated on the projection 74 is one end of a thermostat 75 the other end of which is slidingly mounted in a counterbore 76 of a bore 77 opening into chamber 48. The thermostat 75 is of a known construction wherein a case 78 thereof contains a temperature sensitive material which when heated expands with a substantial working ability. Since the case 78 reacts on projection 74 and since-it otherwise confines the expansible material, the expansive force is resolved into an outward thrust of a plunger 79 in an axial sense. The said other end of the thermostat, through which. plunger 79 projects, is surounded by a seal 80 inhibiting leakage between the oil and fuel circuits. An interponent rod 81 engages at its one end the plunger 79, extends axially through counterbore 76 and bore 77 into chamber 48 where it abuts stem 67 of valve57, the stem 67 and rod 81 being axially aligned. A compression spring 82 is confined in counterbore 76 and urges the rod 81 into continuous contact with the plunger 79, this spring serving a further function in returning plunger 79 inward and re-compressing the temperature sensitive material in case 78 under lowering temperature conditions.

The thermostat 75 is disposed in chamber 53 in the path of fuel flowing to the fuel outport 57. It accordingly senses the temperature of the fuel after leaving the heat exchange component and after absorbing heat from the oil with which it has been in heat transfer relation in the heat heat exchange component. Rising and lowering fuel temperatures bring about extension and retraction of the plunger 79. An increase in what may be termed fuel out temperature above a selected value, indicating excessive oil cooling, results in the rod 81 being projected sufficiently to unseat valve 57. A greater or lesser amount of oil is permitted under this condition to flow directly through opening 52 to the oil outlet port 56, by-passing the heat exchange component. A mixture of cooled and uncooled oil will leave the device by way of outlet port 56, it being understood that the construction and arrangement of parts is such as to return conditioned oil from the heat exchange device at a substantially constant temperature.

The valve construction lends itself to simplified assembly and disassembly, as well as simplified form of calibration. Removal of the end closures 62 and 69 provides wide openings at opposite ends of the valve body through which the thermostat and valve components may be readily installed and removed. All elements of the valve are in line with one another and readily accessible. Calibration of the valve is possible after assembly and does not require that parts he removed for machining or adjustment or in order that shims may be inserted or removed. Thus, after assembly, in a test stand installation oil is circulated through the oil side circuit, that is, into the device by way of inlet port 55, through passage 48 and back to the oil outlet port by way of chamber 51. The valve body 37 may or may not be welded to the heat exchange component at this time. The pressure of the incoming oil is raised until a pressure differential between the oil inlet port 55 and the oil outlet port 56 reaches a value which has been predetermined to be the value at which it is desired that valve 57 should open. Should valve 57 open prior to the reaching of this pressure difference, end closure nut 62 is rotated to compress spring 64 and apply a greater thrust to valve 57 in a closing direction. Should the valve 57 remain closed after the predetermined pressure difference has been reached, the end closure 62 is rotated in an opposite sense to relieve the compression of spring 64. Incremental adjustments of the nut 62 are made in this manner as required to arrive at a proper, selected opening pressure for valve 57.

In calibrating thermostat 75, fuel is put through the fuel side circuit with the temperature being raised to a selected value, beyond which higher temperatures indicate excessive cooling. It is desired that at or about the selected high temperature value rod 81 should engage stem 67 and unseat valve 57. Accordingly, with the fuel out temperature stabilized at the high selected value, the peripherally threaded end closure 69 is adjusted as required to effect corresponding longitudinal adjustments of the thermostat 75. At the selected temperature value plunger 79 is extended a predetermined distance. This distance should be enough so that the extremity of rod 81 contacts the extremity of stem 67 without, however, unseating valve 57. If the parts are not so positioned end closure 69 is adjusted for axial re-positioning of thermostat 75 to bring about the desired relationship of the parts. The relative position of the stem 67 and rod 81 may be visually and hand checked through the oil inlet port 55.

Referring to the heat exchanger component, the bending upward and inward of marginal edges of the plates 15 and .16 create channels which are open where not closed by the manifold sections 38, 39 or 41. Thus, and referring to FIG. 8 for example, the plate 16 has at what may be considered its closed end small laterally spaced openings 83. Similar openings are formed at opposite ends of the assembly in plates 15, at what may be considered the closed side thereof. In final assembly sets these openings serve a useful purpose since they allow flushing and draining of the heat exchanger interior. The salts used in the brazing process have a corrosive effect if allowed to remain after brazing. The holes 83 provide convenient and effective drains assuring a clean, corrosion resistant interior for the heat exchanger component. After flushing and draining the openings 83 may be closed by the deposit of weld metal.

The invention, as noted, has particular reference to oil cooling and like devices, particularly devices of this nature made small, compact and light weight for aircraft and similar use. The invention has, however, general application to heat exchangers and heat exchanger-valve combinations. Further, it is apparent that the apparatus lends itself to extensive structural modification without departing from the spirit of the invention as disclosed.

The plates 15 and 16 have been described as being in an alternating arrangement, this being optional for most efiicient heat transfer. Like plates may be adjacent to one another, however, where dimensional or other circumstances may require. In the illustrated instance a pair of plates 15 are superposed in the mid section of the heat exchanger.

While chambers 27 and 28, and segmental fins 29 and 31 therein have been described as generally triangular, base portions thereof have parallel sides. The result is to achieve a guided flow of the oil in a manner to inhibit short circuiting between openings 21 and 22. Oil entering opening 21 is restrained from turning and moving immediately to opening 22. Instead it is guided to interior portions of fin strip 26, making maximum use of provided heat transfer surface.

What is claimed is:

1. A valve device for controlling flow of a first fluid by reference to its pressure and to the temperature of a second fluid, including a valve body having a first passage through said body for flow of said first fluid to a heat exchanger or like conditioner and a second passage through said body for flow of said first fluid from said heat exchanger or the like, said body providing a by-pass opening between said passages, and said body further having a third flow passage therethrough for said second fluid; end openings in said body aligned with one another and with said by-pass opening; closure members installed in said end openings and having a screw threaded mounting therein to be axially adjustable in response to rotation thereof; a valve adapted to seat in said body to close said by-pass opening, said valve opening in response to a predetermined pressure difierential between said first and second flow passages; a compression spring seated on one of said closure members and urging said valve to a closed position, the pressure of said spring changing with axial adjustment of said one closure member to vary the pressure differential at which said valve opens; a thermostat installed in said body to be influenced by the temperature of the said second fluid flowing through said third passage, said thermostat being based to react against the other one of said closure members and having a plunger extensible under the effects of rising temperature; spring means returning said plunger under the effects of lowering temperature and urging said thermostat to a seat on said other closure member, said thermostat being axially movable in said body, said spring being based in said body; and a rod extending from said plunger to engage said valve effective upon a predetermined extension of said plunger under rising temperature to lift said valve from its seat to an open position irrespective of the pressure differential between said first and second passages, said thermostat being bodily axially adjustable under the opposing thrust of said other closure means and of said spring means to vary the axial position of said rod relative to said valve, said valve device being calibrated with respect to the temperature at which said valve opens and the pressure at which it opens while the device remains asembled merely by the incremental turning of said end closures.

2. A valve device according to claim 1, wherein said first flow passage is disposed intermediately of said second and third flow passages, said valve having an axial reduced diameter extension projecting through said bypass opening into said first flow passage, said rod projecting from said plunger into said first chamber in axial alignment with said valve extension and adapted to engage said extension to unseat said valve.

3. A valve device according to claim 2, wherein said body provides an externally accessible opening defining an inlet to said first flow passage, said inlet opening providing a means of visually and hand checking of the relative positions of said rod and valve extension in the temperature calibration of said valve device.

References Cited UNITED STATES PATENTS 2,653,797 9/1953 Jensen 23634.5 X 2,809,810 10/1957 Carroll l-37 EDWARD J. MICHAEL, Primary Examiner 

